Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [reverse-breakdown]

36 questions
57
votes
5 answers

Are LEDs better than we think?

Conventional wisdom about LEDs says their maximum reverse voltage \$V_{R(max)}\$ is quite limited, usually in the 5V-8V range. So, for experimentation purposes, I wanted to bring an LED into controlled breakdown, using my current-limited power…
LorenzoDonati4Ukraine-OnStrike
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1 answer

Are reverse biased transistors stable?

The usual circuit (found widely across the internet) for a true random number generator's (TRNG) entropy source is a reverse biased transistor like so: Q1 is typically a 2N3904 as it has been found to be quite noisy the wrong way round running in…
Paul Uszak
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How to avoid or compensate for reverse biased base-emitter breakdown in this BJT active clamp design?

This active clamp design is elegant and simple, and works well to prevent OUT from exceeding the supply voltage (+15V), but fails when IN is low enough to reverse bias Q1's base-emitter junction beyond its reverse-breakdown voltage. When this…
Simon Fitch
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How protective diode protects transistor from breakdown?

Please, explain the process of breakdown; how exactly this protective diode protects the transistor? In a Horowitz & Hill book, "The Art of Electronics", 2nd edition, in "Chapter 2 - Transistors" (page 68), i read the following: Always remember…
yulian
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7
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8 answers

Maximum reverse voltage applied to a resistor-LED configuration

Consider the simple circuit below: simulate this circuit – Schematic created using CircuitLab LED datasheet: link Will the applying of a reversed 36 V to this circuit damage the LED? Knowing that the maximum current that could flow into the LED is…
fhlb
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6
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TVS diode specs - clamping voltage lower than breakdown voltage?

Having read this app note (and a few others) and quite a number of TVS datasheets, I came across one that is bugging me a bit. All of the TVS datasheets that I have read so far describe the the following concept (below curve is for a unidirectional…
wave.jaco
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Why does output of this reverse bias noise source not have normal distribution?

I am trying to build a noise source based on reverse biased PN junction (i am trying to replicate this project https://altusmetrum.org/ChaosKey/ ). At this point i tried multiple iterations but so far this is my best result achieved. The noise…
pigster
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Diode emission coefficient and saturation current

I have created a Zener diode model in LTSpice, and now I am trying to simulate it with different values of the saturation current (IS), emission coefficient (N) and breakdown voltage (BV) using Spice. These terms are not entirely clear to me, so…
abruzzi26
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Distinguish if this component is a PIN Photodiode or an APD Avalanche Photodiode

I am experimenting with a DFB Laser salvaged from a scrapped GPON Router. Laser works fine, but it comes with what looks like a "Built in InGaAsP monitor photodiode" incorporated into the laser. Here is a picture of how it looks like: Pinout…
Ezequiel Adrian
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BJT Base-Emitter Reverse Breakdown

In the following (partial) circuit, the transistor is usually in its regular forward active mode. However, when the supplies collapse abrubtly - e.g. during power-down - the base-emitter junction can be transiently reverse biased with more than the…
tobalt
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APD (Avalanche Photodiode) Active Quenching Circuit (AQC) Waveforms & Circuit Behavior

I am reading a paper tiled Avalanche photodiodes and quenching circuits for single-photon detection The paper presents an Active Quenching Circuit schematic, briefly describes its operation, and shows the voltage waveforms for nodes of interest. I…
Cole Fehr
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How to reduce NPN reverse base current on this interesting "Super Efficient Joule Thief"?

Note: The question part is the fixing of the negative current at the transistor base. It looks like there's a problem with negative current at the LED(s) -- this is not expected to be answered in this question, but will be a separate question, if…
MicroservicesOnDDD
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Zener diode - Zener voltage vs reverse voltage specification

This may be a very simple question with a straight-forward answer, but I cannot get a clear answer on this. Consider the following Zener diode. The table on page 2 lists a column for Zener voltage \$V_Z\$ and also a column for Reverse voltage…
wave.jaco
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2
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1 answer

reverse bias of the gate of an N-channel enhancement mosfet

So how negative can I drive the Vgs of an N-channel Mosfet before damage occurs? Datasheets specify BVDSS and BVGSS but these are "forward" breakdown voltages -- ie the absolute maximum Vds before avalanche breakdown of the drain body pn junction,…
jrive
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Can reverse breakdown voltage be used to simulate lifetime aging of phototransistors?

As phototransistors age, their responsivity to light decreases (a fixed amount of light generate less photocurrent). To simulate long-term aging of phototransistors in a short period of time, one can conduct accelerated lifetime testing by exposing…
ach-agarwal
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